An epoxy resin composition has excellent electric performance and adhesivity, therefore, conventionally it has been used for various fields of electricity and electronics.
In addition, when sufficient heat resistance properties can not be obtained even though an conventional epoxy resin is used alone or in combination, high heat resistant cyanate-epoxy composite resin compositions comprised of mixing epoxy resin with cyanate ester resin are commonly used as sealing materials of semiconductor or used for moldings such as base board for electronic circuit etc.
However, liquid epoxy resin compositions used for sealing semiconductors comprised of cyanate ester, epoxy resin, inorganic filler and dihydrazide compound etc. (Patent document 1) had disadvantages in that a high temperature in curing or long curing time is required as well as each curing agent against cyanate ester and epoxy resin may be required, respectively.
Patent document 1: Japanese Unexamined Patent Publication Tokkai 2001-302767
It is proposed that an amine curing agent is used for the composite composition containing cyanate ester and epoxy resin (Patent document 2). However, in this case, there was a disadvantage in that sufficient storage stability was not obtained.
Patent document 2: Japanese Unexamined Patent Publication Tokkai-sho 60-250026
Furthermore, the heat curable resin composition, wherein a potential curing agent containing imidazole component is used with cyanate ester and epoxy resin, should be limited in the quantity of cyanate resin used to obtain sufficient stability (Patent document 3). Thus, a satisfactory heat curable resin composition has not been obtained yet.
Patent document 3: Japanese Unexamined Patent Publication Toku hyo 2001-506313